cp's OEIS Frontend

A358003 Least composite number k such that there are n digits in the intersection of the sets of digits of k and of the juxtaposition of prime factors of k (apart from multiplicity).

%I A358003 #29 Oct 26 2022 07:59:11
%S A358003 4,12,95,132,1972,12305,104392,1026934,10298746,102367895,1023485967
%N A358003 Least composite number k such that there are n digits in the intersection of the sets of digits of k and of the juxtaposition of prime factors of k (apart from multiplicity).
%e A358003 a(0) = 4 = (2*2) there are 0 digits in the intersection of {4} and {2}, and no lesser composite with this property exists.
%e A358003 a(1) = 12 = (2*2 * 3)
%e A358003 a(2) = 95 = (5 * 19)
%e A358003 a(3) = 132 = (2*2 * 3 * 11)
%e A358003 a(4) = 1972 = (2*2 * 17 * 29)
%e A358003 a(5) = 12305 = (5 * 23 * 107)
%e A358003 a(6) = 104392 = (2*2*2 * 13049)
%e A358003 a(7) = 1026934 = (2 * 463 * 1109)
%e A358003 a(8) = 10298746 = (2 * 1069 * 4817)
%e A358003 a(9) = 102367895 = (5 * 7 * 109 * 26833)
%e A358003 a(10) = 1023485967 = (3*3 * 7 * 16245809)
%o A358003 (PARI) card(k)=my(u=Set(digits(k)), m=factor(k), v=[]); for(i=1, #m~, v=setunion(v, Set(digits(m[i, 1])))); #setintersect(u, v)
%o A358003 a(n)=if(n>10,return(0));forcomposite(k=10^(n-1), ,x=card(k);if(x==n,return(k)))
%K A358003 nonn,base,fini,full
%O A358003 0,1
%A A358003 _Jean-Marc Rebert_, Oct 24 2022